Hydraulic setting tool with pressure multiplier

A hydraulically operated setting tool for use in setting a plug or other component in a wellbore, said tool being responsive to a supply of input actuating pressure to actuate the tool, and compromising;

• an elongate housing which is moveable lengthwise during lowering and raising movement of the tool in the wellbore, said housing having an inlet to receive the supply of actuating pressure;
• an actuator element axially displaceable relative to the housing and engageable with said component to set and release said component with respect to the wellbore;
• and
• a pressure multiplier arrangement comprising at least two linked but independent pressure generating members in the housing and operative, upon supply of actuating pressure to the housing, to provide a low pressure high volume output to perform the initial loading of the tool, and a high pressure, low volume output to provide a multiplied hydraulic force applied to the actuator element to set said component in a required position in the wellbore.